Inclusion of Organic Cations by Calix[n]arenes

Calix[n]arenes represent an interestingclass of preorganized aromatic hostsexhibiting an enhanced ability forcation- interaction. Recent resultsobtained with the complexation of variouscalix[n]arenes and five structural typesof organic cations, namely ammonium ions,quaternary ammonium ions, phosphonium ions,iminium ions and tropylium ions are reviewed.The influence of both the guest structure and theshape and flexibility of the hosts on the complexstability in the gas phase and (mainly) in solutionis considered.     

Anti-thrombotic Activity of Water-soluble Calix[n]arenes

The parent p-sulfonato-calix[n]arenes and six O-monosubstituted derivatives were investigated in vitro for anticoagulant activity. Different concentrations of calixarenes were tested, showing that the compound 49-mono-(2-carboxymethoxy)-5,11,17,23,29,35,41,47-octa-sulfonato-calix[8]arene (C8SMA) has a significantly strong prolongation on the activated partial thromboplastin time (APTT) and on the thrombin time (TT) than the other calixarenes. Secondly, investigation of whether the anticoagulant behaviour was via interaction with antithrombin or Heparin Cofactor II was determined. Thrombin inhibition mediated by antithrombin (AT) and Heparin Cofactor II (HCII) activation was investigated in comparison to the biological activators, Heparin (Hep) and Dermatan sulfate (DS). The results show that the 49-mono-(2-carboxymethoxy)-5,11,17,23,29,35,41,47-octa-sulfonato-calix[8]arene (C8SMA) and 5,11,17,23,29,35-hexa-sulfonato-calix[6]arene (C6S) produce activation of HCII at 500 μM comparable to that induced by DS at 100 μM. However, activation of AT by all of the investigated calixarenes is between 10 and 50 times lower than that observed in the presence of heparin. The mechanism of the anticoagulant effect of these calixarenes is as activators of HCII and not as activators of AT.     

杯芳烃酰胺类衍生物对金属离子的萃取性能

以吗啉和六氢吡啶修饰的四种对叔丁基杯[n]芳烃酰胺类衍生物(n=6,8)为萃取试剂,研究了它们对Na+,K+及部分过渡金属等十种金属离子的萃取作用.结果表明此类杯芳烃酰胺类衍生物对过渡金属离子有良好的选择性识别作用.其中,吗啉取代基修饰的杯[8]芳烃萃取效果最好.     

Anti-thrombotic Activity of Water-soluble Calix[n]arenes

The parent p-sulfonato-calix[n]arenes and six O-monosubstituted derivatives were investigated in vitro for anticoagulant activity. Different concentrations of calixarenes were tested, showing that the compound 49-mono-(2-carboxymethoxy)-5,11,17,23,29,35,41,47-octa-sulfonato-calix[8]arene (C8SMA) has a significantly strong prolongation on the activated partial thromboplastin time (APTT) and on the thrombin time (TT) than the other calixarenes. Secondly, investigation of whether the anticoagulant behaviour was via interaction with antithrombin or Heparin Cofactor II was determined. Thrombin inhibition mediated by antithrombin (AT) and Heparin Cofactor II (HCII) activation was investigated in comparison to the biological activators, Heparin (Hep) and Dermatan sulfate (DS). The results show that the 49-mono-(2-carboxymethoxy)-5,11,17,23,29,35,41,47-octa-sulfonato-calix[8]arene (C8SMA) and 5,11,17,23,29,35-hexa-sulfonato-calix[6]arene (C6S) produce activation of HCII at 500 μM comparable to that induced by DS at 100 μM. However, activation of AT by all of the investigated calixarenes is between 10 and 50 times lower than that observed in the presence of heparin. The mechanism of the anticoagulant effect of these calixarenes is as activators of HCII and not as activators of AT.in final form: 24 November 2004This revised version was published online in July 2005 with a corrected issue number.     

Controlled self-assembly by mono-p-sulfonatocalix[n]arenes and bis-p-sulfonatocalix[n]arenes

The complexation-induced critical aggregation concentrations of 1-pyrenemethylaminium by mono-p-sulfonatocalix[n]arenes and bis-p-sulfonatocalix[n]arenes (n=4, 5) were systemically measured by fluorescence spectroscopy. In all cases, the complexation-induced critical aggregation concentration decreases by about 3 times upon addition of p-sulfonatocalix[n]arenes. However, the optimal molar ratios for the aggregation of 1-pyrenemethylaminium by mono-p-sulfonatocalix[n]arenes and bis-p-sulfonatocalix[n]arenes are distinctly different: For mono-p-sulfonatocalix[n]arenes, the optimum mixing ratio for the aggregation of 1-pyrenemethylaminium is 1:4 mono-p-sulfonatocalix[n]arenes/1-pyrenemethylaminium, whereas only 2.5 molecules of 1-pyrenemethylaminium can be bound by one cavity of bis-p-sulfonatocalix[n]arenes. The intermolecular complexation of mono-p-sulfonatocalix[n]arenes and bis-p-sulfonatocalix[n]arenes with 1-pyrenemethylaminium led to the formation of two distinctly different nanoarchitectures, which were shown to be nanoscale vesicle and rod aggregates, respectively, by using dynamic laser scattering, TEM, and SEM. This behavior is also different from the fiber-like aggregates with lengths of several micrometers that were formed by 1-pyrenemethylaminium itself above its critical aggregation concentration. Furthermore, the obtained nanoaggregates exhibit benign water solubility, self-labeled fluorescence, and, more importantly, temperature responsiveness.     

Bridged Calix[6]arenes

Bridging including capping of calix[6]arene is not only an importantroute to synthesize new host molecules, but also an efficient route to reduce the mobility of conformationof calix[6]arene. This article reviews the syntheses, conformations and complexation behavior of this kindof host molecules.     

Solvent Extraction of Sodium and Potassium Ions by Dicarboxylated Calix[4]arenes

The extraction of sodium and potassium ions by 25,27-dicarboxymethyl-26,28-dimethoxy-5,11,17,23-tetra-tert-butyl calix[4]arene (L1H2) in chloroform shows the formation of MLIH and M2LI complexes (M = Na, K). In 1,2-dichloroethane, the MLIH species are formed in the acidic pH range, while only the Na2LI species is found at high pH values. The corresponding extraction equilibrium constants K11 (M) and K21 (M) have been evaluated and show a selectivity in favour of Na+ as compared to K+, whatever the nature of the complexes. In chloroform, this selectivity is much more pronounced considering the 2 : 1 complexes: K11(Na)/K11(K) K21(Na)/K21(K).The coexistence of 1 : 1 and 2 : 1 metal : ligand complexes is also shown in the extraction of sodium in 1,2-dichloroethane by the 25,27-dicarboxymethyl-26,28-dimethoxyethoxy-5,11,17,23-tetra-tertbutyl calix[4]arene (LIIH2), locked in the cone conformation.Structural data of the complexes are discussed on the basis of 1H-NMR spectra. In particular, for LIH2, a conformational change from cone to partial cone upon metal complexation has been evidenced for the complexes KLIH, K2LI and Na2LI.     

A Quantum Chemical Study on Recognition of Nitro-phenols by Calix[n]arenes

A PM3 calculation in vacuum of the inclusion complexation ofo-, m-, p-nitro-phenol with calix[n]arenes is performedsuccessfully. The pathways for inclusion process are describedand the most probable structures of the 1:1 complex are soughtthrough a potential energy scan. The energy differences betweenthe inclusion complexes and the hosts, by calculation, show thatthe most stable complexation is calix[4]-p-nitro phenol andcalix[6]-m-nitro phenol.     

Calix[n]arenes as Synthetic Membrane Transporters: A Minireview

Several potential applications of functionalized calix[n]arenes as carriers in transport through membranes of various biological compounds aiming their separation are reviewed. Specific aspects of membrane transport and the use of calix[n]arenes for building synthetic ion channels are discussed.     

Rotaxanes and Catenanes Derived from Tetra-Urea Calix[4]arenes

Summary: Calix[4]arenes, substituted by four urea groups at their wide rim, form dimeric capsules in apolar solvents, which are held together by a seam of intermolecular hydrogen bonds. The heterodimerisation of tetra-aryl and tetratosyl ureas was used to synthesize various derivatives, in which adjacent urea residues are connected to form two, three or four loops. The aliphatic connections were tied by olefin metathesis between adjacent alkenyl residues followed by hydrogenation. Heterodimers of tetra-alkenyl substituted tetra-ureas and bis- or tetraloop derivatives were converted analogously to multiple catenanes. Tetra[2]rotaxanes were obtained in a similar manner. In addition to the spectroscopic evidence (NMR, MS) several compounds were confirmed by crystal structures.     

Synthesis of p-Formylphenylazo Calix [ 4 ]arenes

Calixarenes are a versatile class of macrocyclic compounds, which have attracted extensive interest due to their ability to form host-guest complexes and act as enzyme mimic. Moreover, a number of calixarenes with D-π-A units have been synthesized, and their second-order nonlinear optical (NLO) properties investigated.     

Synthesis of Pyridylazo-substituted Chromogenic Calix[4]arenes

Calixarenes are a versatile class of macrocyclic compounds which have attracted extensive interest due to their ability to form host-guest complexes and act as enzyme mimic, especially when appropriately functionalized1. Introduction of azo group to calixarenes can make the later to be easily detected in the process of molecular recognition, azo groups have been introduced into calixarenes by the diazo-coupling reaction of calix[4]arene with BF4- or chloride salt of substituted benzene diazon…     

Selective Upper-Rim Adamantylation of Calix[4]arenes

Lower-rim mono- and diacylated calix[4]arenes [acyl = C₆H₅CO, 3,5-(NO₂)₂C₆H₃CO] undergo selective adamantylation with 3-Y-1-adamantanols (Y = H, i-Pr, 4-MeC₆H₄) in trifluoroacetic acid at the free phenolic fragments of the macroring. The reaction provides a convenient preparative route to di-, tri-, and tetraadamantylated calix[4]arenes.     

对叔丁基杯[n]芳烃酰胺衍生物的合成及其对某些金属离子的萃取性能

对叔丁基杯[n]芳烃酰胺衍生物的合成及其对某些金属离子的萃取性能;杯芳烃; 酰胺衍生物; 金属离子; 萃取; 离子识别     

Calix[n]arenes mediated phase‐transfer catalytic synthesis of purine derivatives

A new route was designed to achieve the synthesis of purine derivatives under phase‐transfer catalysis conditions using calix[n]arenes TAC_nA (n = 4, 6, and 8) as phase‐transfer catalyst for the first time in this particular type of synthesis. The compounds were synthesized in excellent yields (70%–80%) and the structures were established on the basis of consistent IR, ¹H NMR, FAB‐Mass, and elemental analyses data. Their purity has been ascertained by chromatographic resolution using acetonitrile, methanol, and water (50:30:20, v/v) as eluenting system. Moreover, the kinetics of the reaction was studied and it was found to obey first‐order kinetics. Effect of various parameters, namely, temperature, amount of catalyst, stirring speed, and so on was also investigated. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 41: 265–274, 2009     

杯芳烃和柱芳烃桥梁部位的衍生及其功能化

随着大环化学的快速发展,对杯芳烃、柱芳烃及其他类似化合物的桥梁亚甲基部位进行高效修饰的方法日益引起人们的关注.桥梁部位修饰后的大环衍生物,在不改变其原有属性的基础上增加了新的功能,不仅可以引入更多的功能基团,而且可以通过主客体的自组装行为,进一步拓展杯芳烃和柱芳烃等超分子大环在药物递送、化学传感、荧光体系构建等诸多领域...     

New Wide Rim Phosphomethylated Calix[4]arenes in Extraction of Americium and Europium

A new series of the cone-shaped tetraalkoxycalix[4]arenes substituted at the wide rim with four phosphomethyl groups have been synthesized by the Arbuzov, Michaelis–Becker and Aterthon–Todd reactions of the chloromethyl or phenylhydrophosphinylmethylcalix[4]arenes. Their binding properties towards Eu³⁺ and Am³⁺ cations were investigated by the liquid–liquid extraction method. Due to the ‘calixarene effect’ the tetraphosphorylated calixarenes are more effective extractants for the metal cations than their acyclic analogs or some industrial extractants such as trialkylphosphinoxides, carbamoylphosphinoxide, bis-2-diethylhexyl phosphoric acid.     

Preferred Conformations of Calix[4]- and Calix[6]arenes,Calculated ab initio

Ab initio STO-2G calculations showed that the preferred conformation of a series of calix[6]arenes substituted at the upper rim is a compressed cone stabilized by a pseudo-ring of six hydrogen bonds with close characteristics. The endocyclic dihedral angles between the benzene ring planes, characterizing the molecular shape of the above macrocyclic compounds in this conformation, were calculated. The calculation results are consistent with the conformational data obtained by other theoretical methods and describe the characteristics of hydrogen bonds more adequately, in agreement with the experimental data and with the existing concepts of the hydrogen bonding efficiency.     

杯芳烃树枝型酰胺衍生物的合成和对金属离子的识别

杯芳烃树枝型酰胺衍生物的合成和对金属离子的识别;杯芳烃;树枝型化合物;酰胺;离子识别;紫外-可见光谱     

Fullerenes Enclosed in Bridged Calix[5]arenes

Host systems that bind C ₇₀ preferentially to C ₆₀ are found in the bridged calix[5]arenes 1 (X= alkyne bridge). The complexation-induced shifts of the bound fullerene guests provide valuable information on the structure and dynamics of the supramolecular complex.